Intermittent urinary catheter

ABSTRACT

A catheter has an entrance opening defined by the first end of a catheter body and non-circular inner surface in cross section. The entrance opening intersects a longitudinal axis extending longitudinally through the center of a lumen adapted to drain urine from a bladder. The non-circular inner surface can have dimples, channels, or grooves, all of which decrease frictional fluid forces against the inner surface as the urine drains. The catheter is free of any eyelets formed in the side wall of the catheter body. The catheter further includes a plurality of distinct longitudinally extending convex outer surfaces and may have an enlarged head.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation in part application that claims priority from U.S. patent application Ser. No. 13/922,667, filed Jun. 20, 2013; the disclosure of which is entirely incorporated herein by reference as if fully rewritten.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates generally to a medical device. More particularly, the invention pertains to a catheter for draining urine from a bladder. Specifically, the invention provides a catheter having an opening at a first end and a sidewall that is free of eyelets, and wherein the catheter is configured to drain urine from a patient's bladder faster than conventional catheters.

2. Background Information

Urinary catheters are extremely useful medical devices. Generally, a urinary catheter is inserted into the urethral canal of a patient to drain urine from the bladder when they need assistance urinating. Current catheter designs have a catheter body sidewall with two to four eyelets or intake apertures formed in the catheter body sidewall at one end and often a hemispheric tip enclosing one end to facilitate insertion into a urethral canal. The eyelets are known to those in the urology field to cause trauma to the urethra. During insertion, the edges of the eyelets can cut the urethra wall, similar to the way a box grater or box shredder cuts a piece of cheese, often leading to serious infections requiring extreme medical attention.

Improvements on this basic design have come and gone through the years, such as smoother and polished eyelet designs to decrease the risk of infection often attributed to insertion agitation. Yet, these catheters still have drawbacks. Slow drainage time is often a problem because the eyelet formed in the catheter body sidewall causes turbulent fluid forces within the catheter. Further, friction forces created by the urine flow contacting the inner surface of the catheter decreases the fluid flow or drainage rate. The eyelets also have a likelihood of becoming clogged with mucus or debris contained in the bladder, or clogged with lubricant used during the insertion process.

SUMMARY

Inasmuch as drawbacks continue to exist with respect to currently known intermittent urinary catheters as detailed by way of background above, there is a need in the art for an improved catheter that addresses some or all of the drawbacks of the currently known designs. The present invention addresses some of these issues.

In one aspect, an embodiment may provide an improved catheter that has a single entrance opening located at the first end instead of the two to four eyelets formed in the sidewall of conventional catheters. Further, the improved catheter maintains a faster flow rate with one entrance opening than the flow rate of a conventional catheter having two eyelets. The improved catheter is structurally strong enough to allow the entrance opening to be introduced first into the urethral canal without the need for a tip.

In one aspect, an embodiment may provide a catheter comprising: a generally cannular body having an annular sidewall with first and second ends that therebetween define an longitudinal axis, said first end adapted to be inserted into a urethral canal; said body having an outer surface spaced apart from an inner surface; a lumen defined by the inner surface adapted to drain the fluid from a bladder; and a single entrance opening defined in the first end wherein a plane of the opening intersects the longitudinal axis.

In another aspect, another embodiment may provide a catheter comprising: a body having an annular sidewall extending along a longitudinal axis between first and second ends, said body having an outer surface spaced apart from an inner surface; a lumen defined by the body extending longitudinally from first end to second end adapted to drain fluid from a hollow organ; and an entrance opening formed in the first end in longitudinal alignment with the lumen and including an entrance opening plane intersecting the axis in a generally perpendicular manner.

In another aspect, another embodiment may provide a catheter comprising: a catheter having first and second ends with a generally cannular body extending therebetween along a longitudinal axis; said body having an outer surface spaced apart from an inner surface; said inner surface having a non-circular cross section when viewed from above; a lumen defined by the non-circular inner surface adapted to drain fluid from a hollow organ; and an entrance opening formed in the first end in fluid communication with the lumen.

In yet another aspect, an embodiment may provide a method for draining a human bladder comprising the steps of: providing a catheter having an annular sidewall with first and second ends that therebetween define a longitudinal axis, and having an entrance opening defined in the first end of the body; wherein a plane of the opening intersects the longitudinal axis; aligning the first end of the catheter body with the entrance to a patient's urethral canal; inserting the first end of the catheter into the urethral canal; moving the catheter through the urethral canal towards the patient's bladder; establishing fluid communication between the catheter and the bladder; causing urine to flow from the bladder through the entrance opening; through a lumen defined in the catheter, where the lumen is longitudinally aligned with the entrance opening; through an aperture defined in the second end of the catheter body, where the aperture is longitudinally aligned with the lumen; and into a drainage tube engaged with the second end of the catheter body; draining a quantity of urine from the bladder; and removing the catheter after the quantity of urine has drained from the bladder.

Still further, an embodiment may provide an intermittent urinary catheter comprising: a generally flexible tubular body member defining a lumen extending centrally along a longitudinal axis from a first end to a second end, said first end adapted to be inserted into a urethral canal of a patient; an outer surface spaced apart from an inner surface of the tubular member, wherein the inner surface defines the lumen adapted to drain the fluid from the patient's bladder; and a plurality of distinct longitudinally extending convex surfaces positioned circumferentially about the longitudinal axis collectively defining the outer surface.

In another aspect, an embodiment may provide an intermittent urinary catheter comprising: a generally flexible tubular body member defining a lumen extending centrally along a longitudinal axis from a first end to a second end, said first end adapted to be inserted into a urethral canal of a patient; an outer surface spaced apart from an inner surface of the tubular member, wherein the inner surface defines the lumen adapted to drain the fluid from the patient's bladder; an entrance opening formed adjacent the first end of the of the tubular body member in fluid communication with the lumen; and an enlarged tip formed adjacent the first end of the tubular body member, the enlarged tip having a diameter greater than that of the tubular body member, said enlarged tip adapted to guide the intermittent urinary catheter through the urethral canal.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

A sample embodiment of the invention, illustrative of the best mode in which Applicant contemplates applying the principles, is set forth in the following description, is shown in the drawings and is particularly and distinctly pointed out and set forth in the appended claims.

FIG. 1 is a perspective view of a PRIOR ART catheter having two eyelets in the catheter's sidewall and a hemispheric tip at a first end of the catheter;

FIG. 2 is a cross section view taken along line 2-2 in FIG. 1 depicting a PRIOR ART catheter having two eyelets in the body sidewall that do not intersect the longitudinal axis and having a smooth inner and outer surface;

FIG. 3 is a diagrammatic view of the catheter of the present invention depicting it in vivo utilization;

FIG. 4A is a top view of a first end of a first embodiment of the present invention depicting a catheter body which is of a substantially constant outer diameter along its length, and showing a first interior variation of a catheter lumen having an inner surface with connecting longitudinal channels;

FIG. 4B is a cross section view taken along line 4B-4B in FIG. 4A;

FIG. 5A is a top view of the first end of the first embodiment of the present invention depicting the constant outer diameter catheter body and showing a second variation of the lumen having spaced apart longitudinal channels along inner surface.

FIG. 5B is a cross section view taken along line 5B-5B in FIG. 5A;

FIG. 6A is a top view of the first end of the first embodiment of the present invention depicting the constant outer diameter catheter body and showing a third variation of the lumen having a v-shaped channeled inner surface.

FIG. 6B is a cross section view taken along line 6B-6B in FIG. 6A;

FIG. 7A is a top view of the first end of a second embodiment of the catheter depicting a truncated tear drop shaped head and the first interior variation of the inner surface having connecting annular channels;

FIG. 7B is a cross section view taken along line 7B-7B in FIG. 7A;

FIG. 8A is a top view of the second embodiment depicting the truncated tear drop shaped head with the second interior variation having the spaced apart annular channels along the inner surface.

FIG. 8B is a cross section view taken along line 8B-8B in FIG. 8A;

FIG. 9A is a top view of the second embodiment depicting the truncated teardrop shaped head and the third variation of the lumen having the v-shaped channeled inner surface.

FIG. 9B is a cross section view taken along line 9B-9B in FIG. 9A;

FIG. 10A is a top view of the first end of a third embodiment of the catheter depicting a dimpled outer surface and a fourth variation of the lumen having a dimpled inner surface;

FIG. 10B is a side elevation view of the third embodiment of the catheter depicting the convex dimples extending along the outer surface;

FIG. 10C is a cross section view taken along line 10C-10C in FIG. 10A;

FIG. 11A is a top view of the first end of the first embodiment of the catheter depicting a fifth variation of the lumen and showing a smooth inner surface;

FIG. 11B is a cross section view taken along line 11B-11B in FIG. 11A;

FIG. 12 is a top view of the first end of the second embodiment of the catheter and showing the fifth variation of the lumen having the smooth inner surface;

FIG. 13 is a top view of the first end of the third embodiment of the catheter depicting the fifth variation of the lumen having the smooth inner surface;

FIG. 14A is a top view of the first end of the first embodiment of the catheter and the fifth variation of the lumen and showing a plurality of spaced apart friction or tension reducing cutouts positioned at the first end of the inner surface;

FIG. 14B is a cross section view along line 14B-14B in FIG. 14A;

FIG. 15 is a top view of the first end of the second embodiment of the catheter having the fifth variation of the lumen and depicting the plurality of spaced apart friction or tension reducing cutouts positioned at the first end of the inner surface;

FIG. 16 is a top view of the first end of the third embodiment catheter having the fifth variation of the lumen and depicting the plurality of spaced apart friction or tension reducing cutouts positioned at the first end of the inner surface;

FIG. 17A is a top view of the first end of a fourth embodiment catheter having a plurality of distinct convex surfaces on the outer surface;

FIG. 17B is a cross section view taken along line 17B-17B in FIG. 17A;

FIG. 18A is a top view of the first end of the fourth embodiment catheter having a bulbous head and a plurality of distinct convex surfaces on the outer surface extending over the head;

FIG. 18B is a cross section view taken along line 18B-18B in FIG. 18A;

FIG. 18C is a cross section view take along line 18C-18C in FIG. 18B;

FIG. 19A is a top view of the first end of the fourth embodiment catheter having a bulbous head and a plurality of distinct convex surfaces on the outer surface beginning below the bulbous head and a continuous smooth surface of the head;

FIG. 19B is a cross section view taken along line 19B-19B in FIG. 19A;

FIG. 19C is a cross section view take along line 19C-19C in FIG. 19B;

FIG. 20 is a side view of the first end of a fifth embodiment catheter;

FIG. 21 is a side view of the first end of a sixth embodiment catheter;

FIG. 22 is a top view of a catheter having an exemplary internal configuration;

FIG. 23 is a top view of a catheter having another exemplary internal configuration;

FIG. 24 is a side view of the first end of a seventh embodiment catheter;

FIG. 25 is a side view of the first end of an eighth embodiment catheter; and

FIG. 26 is a side view of the first end of a ninth embodiment catheter.

Similar numbers refer to similar parts throughout the drawings.

DETAILED DESCRIPTION

With primary reference to FIGS. 1 and 2, a catheter 10 as conventionally known in the PRIOR ART has a first end 12, a second end 14, a catheter body or annular sidewall 16 extending from first end 12 to second end 14, eyelets 18, a first end wall 20 at the first end 12 that forms a tip which is hemispheric in shape and substantially continuous, a sidewall outer surface 22, a sidewall inner surface 24, and a lumen 26 defined by inner surface 24. Catheter body 16 is generally cannular or tubular extending from first end 12 to second end 14 and defining therebetween a longitudinal axis X_(pa). Eyelets 18 are formed in the catheter sidewall extending from a start plane S_(pa) along outer surface 22 to and end plane E_(pa) along inner surface 24 proximate the first end 12. The respective start and end planes, S_(pa), E_(pa), of the eyelets are parallel to longitudinal axis X_(pa). When viewed from a side cross section (FIG. 2) and extrapolated beyond the respective start and end planes, S_(pa), E_(pa), eyelets 18 are at right angles to the longitudinal axis X_(pa). Eyelets 18 are in fluid communication with lumen 16 permitting fluid to drain through catheter 10 and out and exit opening (not shown) defined in the second end 14, which may be configured to fluidly communicate with a drainage tube or system (not shown). End wall 20 intersects longitudinal axis X_(pa) and is substantially solid and continuous. However, there are some known prior art catheters 10 that may contain a small or “pin-hole” opening within end wall 20, wherein this pin-hole opening has a substantially smaller diameter than the lumen 16 diameter. The outer and inner surfaces 22, 24 of the catheter sidewall 16 are smooth. One exemplary PRIOR ART catheter is commercially known as the Cure Catheter™ 14 Fr., model number M405F1406, manufactured for and distributed by Cure Medical, LLC of Newport Beach, Calif.

The embodiments of the catheter of the present invention are identified using reference number 30A in FIGS. 4A-6B, 11A-11B, and 14A-14B; reference number 30B in FIGS. 7A-9B, 12, and 15; reference number 30C in FIGS. 10A-10C, 13, and 16; reference number 30D in FIGS. 17A-19C; reference numeral 30E in FIG. 20; reference numeral 30F in FIG. 21; reference number 30G in FIG. 24; reference number 30H in FIG. 25; and reference number 30I in FIG. 26.

As will be further described herein, first embodiment catheter 30A has a sidewall 36 that it of a substantially constant diameter from the first end of the catheter to the second end thereof. Second embodiment catheter 30B has a truncated tear-drop shaped first end; and third embodiment catheter 30C has a plurality of dimples on the outer surface of the catheter sidewall. Each embodiment may be configured so that a lumen defined in the catheter has any of five different interior surface configurations, each of which having a unique cross section.

With primary reference to FIGS. 4A-6B, catheter 30A has a catheter body or sidewall 36 (FIG. 3) comprising a top or first end 32, a bottom or second end 34 (FIG. 3), a first or right side 31, a second or left side 33, and an entrance opening 38 defined by the first end 32. Sidewall 36 has an outer surface 40 and an inner surface 42. A lumen 44 is defined by inner surface 42 and lumen 44 extends from first end 32 to second end 34 along a longitudinal axis X. First end 32 to second end 34 therebetween define a longitudinal direction. Right side 31 to left side 33 therebetween defines a radial direction. Catheter sidewall 36 is generally cannular or tubular and extends longitudinally, having a substantially constant outer diameter OD1 from first end 32 to second end 34 centered about longitudinal axis X as seen in device 30A of FIGS. 4A-5B.

In accordance with one aspect of the present invention, entrance opening 38 is defined by catheter sidewall 36 at the first end 32. Entrance opening 38 is a radial, inwardly tapering, through-opening which intersects the longitudinal axis X. Entrance opening 38 extends longitudinally from a tapered start plane TS to a tapered end plane TE. Tapered start plane TS is a radially extending plane at the top end of a tapered annular surface 46. Tapered end plane TE is a radially extending plane at the bottom end of surface 46. Entrance opening 38 is radially bound by surface 46. Preferably, planes TS, TE of entrance opening 38 intersect longitudinal axis X perpendicularly, however other angled relationships are contemplated. Entrance opening 38 has a diameter (ID1, ID2—FIG. 4A) that is substantially the same as the diameter (ID1, ID2—FIG. 4B) of lumen 4. Entrance opening 38 is in longitudinal alignment and in fluid communication with lumen 44. The term longitudinally aligned or longitudinal alignment herein refers to the entrance opening being positioned at the first end and permitting fluid to continue along the same path as lumen 44 without changing directions about longitudinal axis X. Surface 46 permits fluid to flow down the slope thereof and through entrance opening 38. Surface 46 is disposed at an angle α relative to longitudinal axis “X”. Slope a begins at end wall 32A. End wall 32A is located at the first end 32 and comprises a rounded rim that is concentric with opening 38. Tapered start plane TS and end plane TE are each disposed at right angles to longitudinal axis X. As seen in FIGS. 4B, 5B slope α is shown at a 45 degree angle relative to tapered start plane TS, however slope α may be from about approximately 10 to about approximately 80 degrees relative thereto. Further, the taper of surface 46 generally requires sidewall thickness 37 to be approximately 25% greater in device 30A than a body thickness of a prior art catheter 10 having a substantially similar outer diameter.

Inner surface 42 may have five variations of cross sectional shapes or forms when viewed from the first end. It is to be understood that the five forms disclosed herein can be incorporated into any of the three embodiments of device 30A, 30B, and 30C. In a first form, inner surface 42 defines a plurality of channels 50 extending longitudinally and formed within the catheter sidewall 36. As seen in FIGS. 4B, 5B, channels 50 start in the surface 46 between the tapered start plane TS and tapered end plane TE. As shown in FIGS. 4A and 4B, channels 50 are defined by the longitudinally extending recesses 52A which are half-moon shaped when viewed from first end, connected along longitudinally extending edges 52B.

In a second form, as shown in FIGS. 5A and 5B, the channels 50 can be defined by a plurality of longitudinally extending half-moon recesses 52 and arcuate separation sections 51. The half-moon recesses 52 or 52A are spaced annularly apart from one another in a manner so as to increase fluid flow through lumen 44 of catheter 30A relative to that of a conventional circular cross-sectional lumen known in the prior art. The separation sections 51 are generally equally spaced between the half-moon recesses 52.

In a third form, as shown in FIGS. 6A and 6B, channels 50 include at least one section that is straight or planar. In particular, each channel 50 preferably includes two straight sections that form a generally V-shaped channel defined by longitudinally extending edges 54 and connected flat panels 55 forming formed in the inner surface 42 in the catheter sidewall 36. The connected edges 54 and panels 55 provide a generally octagonal cross-section. While this embodiment provides a generally octagonal cross-section, yet other geometric shapes capable of being configured by connected edge 54 and panels 55 are contemplated. Further alternatively, channels 50 may be rifled to increase drainage flow rate. The term rifled in this context means channels 50 may extend concentrically in a helical manner from first end 32 to second end 34 along defined by inner surface 42.

Referring to FIGS. 4A-5B, 7A-8B sidewall 36 has an outer diameter shown as OD1 extending from right 31 to left 33 side of the surface, a first inner diameter shown as ID1, a second inner diameter shown as ID2, and a radial or sidewall thickness 37. Sidewall 36 may alternatively have a third inner diameter ID3 and a fourth inner diameter ID4 as seen in device 30A of FIGS. 6A-6B instead of the first and second inner diameters ID1, ID2. Further alternately, sidewall 36 may have a fifth inner diameter ID5 and a sixth inner diameter ID6 as seen in device 30C of FIGS. 10A-10C instead of the first and second inner diameters ID1, ID2. Even further, sidewall 36 may have a single inner diameter, shown as ID7 in device FIG. 11A-16. Outer diameter OD1 extends from right side 31 to left side 33 of outer surface 40 as viewed from the cross section view in FIGS. 4B, 5B. As seen in the top view of FIG. 5A, first inner diameter ID1 extends radially across axis X between arcuate separation sections 51 and second inner diameter ID2 between half-moon recesses 52. As shown in the top view of FIG. 5B, third inner diameter ID3 extends radially across axis X between longitudinally extending panels 55 and fourth inner diameter ID4 extending radially between edges 54. As shown in the top view of FIG. 10A, fifth inner diameter ID5 extends radially across axis X from side to side 31, 33 of inner surface 42 and sixth inner diameter extends radially across axis X between dimples 62. As seen in FIGS. 4B, 5B, sidewall thickness 37 extends radially between outer surface 40 and inner surface 42. In any of the embodiment illustrated herein, it will be understood that the diameter of opening 38 is substantially of the same diameter of the lumen with which it is in fluid communication.

Ordinarily, catheters are characterized by a scale known as the “French Size”, each French size having a corresponding outer diameter. For example, a catheter having a French Size 4 has an outer diameter of 0.053 inches or 1.35 mm. While a French Size 8 catheter has an outer diameter of 0.105 inches or 2.7 mm. Outer diameter OD1 of the present invention is configured to have the same outer diameter as a conventionally known French size.

With primary reference to FIGS. 7A-9B, a second embodiment of catheter 30B is shown having a bulbous or truncated teardrop-shaped head 56 formed in the first end 32 of the catheter sidewall 36. The truncated teardrop-shaped head 56 extends radially outwardly from longitudinal axis X to provide a second outer diameter OD2 that is larger than the outer diameter OD1 of sidewall 36. Outer surface 40 extends continuously along truncated teardrop-shaped head 56 having a first sloped surface 40A, an apex surface 40B, a second sloped surface 40C, and a sidewall surface 40D when viewed from the side. As seen in FIG. 7B, first sloped surface 40A extends a distance from rounded end wall 32A flared radially outward from axis X towards second end 34. Apex surface 40B is positioned below first sloped surface 40A when device 30B is oriented vertically. Apex surface 40B forms an apex from which the outer diameter OD2 of head 56 is determined. Second sloped surface 40C extends a distance from apex surface 40B flared radially inwards to axis X towards second end 34. Sidewall surface 40D continues from second sloped surface 40C to second end 34.

With continued reference to FIGS. 7A-9B, lumen 44 extends through the truncated teardrop-shaped head 56 in fluid communication with the entrance opening 38 as defined by its surface 46. Channels 50 have the same inner diameter extending from the entrance opening 38 through the truncated teardrop-shaped head 56 and continuing longitudinally through catheter sidewall 36.

With primary reference to FIGS. 10A-10C, the third embodiment catheter 30C has a plurality of convexly-shaped dimples 60 along outer surface 40, a plurality of concavely-shaped dimples 62 along inner surface 42, a plurality outer surface retention areas 43, a first outer diameter OD1, a second outer diameter OD3, first inner diameter ID5, second inner diameter ID6, in addition to other elements having similar reference numerals as the other embodiments. Catheter 30C may have a generally non-circular cross section or textured outer surface 40 and a generally non-circular cross section or textured inner surface 42. Convex dimples 60 are formed along the outer surface 40 in the catheter sidewall 36. The term convex with respect to dimples 60 refers to the dimples extending radially out of the catheter sidewall 36 and the dimple surface facing outward as viewed from above as seen in FIG. 10A. Convex dimples 60 have an outer annular edge 60A and an apex 60B. Annular edge 60A is a generally circular edge disposed where dimple 60 connects to outer surface 40 of sidewall 36. Apex 60B is the apex or radially outermost point of dimple 60 surface when viewed from a cross-sectional side view, as seen in FIG. 10C. Second outer diameter OD3 measures radially from right 31 to left 33 at mirroring apexes 60B. First outer diameter OD1 is the outer diameter of outer surface 40. Retention areas 43 are formed along and bound by the outer surface 40 and the spaces between annular edges 60A. Concave dimples 62 are formed along the inner surface 42 in catheter sidewall 36. The term concave with respect to dimples 62 refers to the dimples extending radially into the catheter sidewall 36.

As seen in FIG. 11A-13, the catheter devices 30A, 30B, and 30C may have a substantially smooth inner surface 42 defining lumen 44 having only a single inner diameter ID7. The smooth inner surface 42 extends from first end 32 longitudinally to second end 34. As seen in FIGS. 11A, 12, and 13, inner surface 42 has a substantially circular cross section. Inner diameter IN is preferably generally equal to inner diameter ID1 in width. Alternatively as seen in FIGS. 14A-16, devices 30A, 30B, and 30C may have a substantially smooth inner surface 42 having an inner diameter ID7 in combination with a plurality of notches 50A. Notches 50A extend circumferentially around axis X and are formed in the first end 32 of sidewall 36. Notches 50A are preferably spaced circumferentially adjacent inner annular recess 46 aligned longitudinally along tapered end plane TE. Notches 50A function to reduce surface tension or fluid frictional forces as fluid flows through the entrance opening 38 into lumen 44 having a smooth surface. Preferably, notches 50A extend longitudinally only a short distance passed tapered end plane TE relative to the entire length of inner surface 42. Further preferably, notches 50A have a generally oval edge when viewed from the side (FIG. 14B) permitting notches to extend radially outward into the first end 32 of catheter sidewall 36.

As depicted in FIGS. 17A-FIGS. 19C, the embodiment of catheter 30D may include a generally flexible tubular body member 36 defining lumen 44 extending centrally along longitudinal axis X from the first end 32 to the second end 34 wherein the first end 32 is adapted to be inserted into the urethral canal 30 of the patient. Catheter 30D further includes an outer surface 69 spaced apart from inner surface 42. Inner surface 42 defines the lumen 44 which is adapted to drain fluid, namely urine, from the patient's bladder 71. Further, catheter 30D includes a plurality of distinct longitudinally extending convex surfaces 72 positioned circumferentially about longitudinal axis X that collectively define outer surface 69. In one embodiment of catheter 30D, convex surfaces 72 extend from adjacent first end 32 towards the second end 34 and in another embodiment of catheter 30D, the plurality of convex surfaces 72 begin at the first end 32 and extend towards the second end 34.

With continued reference to the plurality of convex surfaces 72 defining outer surface 69 of catheter 30D, a first convex surface 74 is positioned next to a second convex surface 76. First convex surface 74 extends arcuately from a first edge 78 to a second edge 80 and having an apex 82 between first edge 78 and second edge 80. First edge 78 and second edge 80 are spaced radially equidistant from longitudinal axis X. Apex 82 is spaced radially away from longitudinal axis X a distance greater than first edge 78 and second edge 80. Second convex surface 76 extends arcuately from first edge 84 to second edge 86 and has an apex 88 therebetween. First edge 84 and second edge 86 are radially equidistant to each other and preferably similarly dimensioned to first edge 78 and second edge 80. Additionally, apex 88 is spaced apart farther from longitudinal axis X than first edge 84 and second edge 86. In one embodiment, apex 88 is radially distanced from longitudinal axis X the same amount as apex 82.

Each one of the plurality of convex surfaces 72 arcuately extends at a radius of curvature. For ease of description, the radius of curvature is explained with reference to first convex surface 74, but applies to each one of the plurality of convex surfaces 72. The radius of curvature for convex surface 74 is determined by Equation (1):

$\begin{matrix} {R_{curv} = \frac{OD}{N}} & {{Equation}\mspace{14mu}(1)} \end{matrix}$

wherein R_(curv) equals the radius of curvature, OD equals the outer diameter of the catheter body measured across the outer surface (as shown in FIG. 17B, OD=OD1), and N equals the number of convex surfaces.

Recall, that the outer diameter of catheter depends on its French size. By way of non-limiting example, for a catheter having French Size 8 with an outer diameter {OD1 in FIG. 17a ; OD for Equation (1)} of about 2.7 mm and eight convex surfaces 72 (as shown in FIG. 17a ), the resulting radius of curvature (R_(curv)) for first convex surface 74 is (R_(curv)=2.7 mm/8 convex surfaces) about 0.33 mm. Additionally, by way of non-limiting example, for a French Size 4 catheter having an outer diameter {OD1 in FIG. 17a ; OD for Equation (1)} of about 1.3 mm and eight convex surfaces 72 (as shown in FIG. 17a ), the resulting radius of curvature (R_(curv)) for first convex surface 74 is (R_(curv)=1.33 mm/8 convex surfaces) about 0.16 mm.

Table 1 presents an example of some radii of curvature found by Equation (1). Are R_(curv) values are presented in millimeters (mm).

TABLE 1 Exemplary R_(curv) values R_(curv) R_(curv) R_(curv) R_(curv) R_(curv) French OD for for for for for Size (mm) N = 4 N = 6 N = 8 N = 10 N = 12 4 1.33 0.333 0.222 0.166 0.133 0.111 6 2 0.500 0.333 0.250 0.200 0.167 8 2.667 0.667 0.445 0.333 0.267 0.222 10 3.333 0.833 0.556 0.417 0.333 0.278 12 4 1.000 0.667 0.500 0.400 0.333 14 4.667 1.167 0.778 0.583 0.467 0.389 16 5.33 1.333 0.888 0.666 0.533 0.444

Table 1 indicates that a radius of curvature for one of the plurality of distinct convex surfaces 72 may be generally in a range from about 0.1 mm to about 1.33 mm.

As depicted in FIG. 17A, all convex surfaces 72 have the same radius of curvature, however other particular embodiments is possible and may even be desired to have differing radii of curvature associated with different ones of the plurality of convex surfaces 72.

First edge 78 of first convex surface 74 connects with second edge 86 of second convex surface 76 to define a longitudinally extending channel 90 therebetween. In the embodiment shown in FIG. 17A and FIG. 17B, channel 90 begins at the first end 32 of catheter 30D and extends towards the second end 34. However in some other embodiments, channel 90 may begin closely adjacent the first end 32 and extend towards the second end 34. Channel 90 is configured to retain a gel based lubricant therein as catheter 30D is advanced through the urethral canal towards the patient's bladder. The lubricant may be applied manually by the patient or in some other embodiments a gel-based lubricant may be pre-packaged inside the catheter packaging such that when the catheter is advanced through an end of the packaging, as it moves through the gel-based lubricant where the gel-based lubricant is retained in channel 90.

Additionally, as depicted in FIG. 17A, channel(s) 90 exists and are defined at each location where one of the plurality of convex surfaces 72 contacts and meets another convex surface circumferentially next to it relative to longitudinal axis X. Thus, while eight channels 90 are depicted in FIG. 17A, it is to be clearly understood that alternative configurations are entirely possible. For example, the plurality of convex surfaces 72 may define four channels 90, or five channels 90, or six channels 90, or seven channels 90, or nine channels 90, or ten channels 90, or eleven channels 90, or twelve channels 90, and so on. Furthermore, catheter 30D depicts eight convex surfaces 72 and eight inner concave channels 50. It is to be understood that the number of concave inner channels 50 does not need to equal the number of convex outer surfaces 72. It is entirely possible to have four inner concave channels 50 and twelve outer convex surfaces 72 on catheter 30D. Similarly, catheter 30D may have four outer convex surfaces 72 and twelve inner concave channels 50. Or, any combination therebetween. The optimized configuration of catheter 30D is dependent on the French size and the desired flow rate for urine leaving the bladder.

As depicted in FIG. 18A and FIG. 18B, catheter 30D may include an enlarged bulbous head 92 having an outer diameter OD2 greater than an outer diameter OD1 of catheter body 36. The plurality of convex outer surfaces 72 begin at the first end of catheter 30D and extend over the enlarged head 92. Additionally, the channels 90 are formed along enlarged head 92.

With continued reference to FIG. 18A, a first apex 94 is disposed circumferentially from a second apex 96 on head 92. First and second apexes 94, 96 are farther away from longitudinal axis X than apex 82 and apex 88 on catheter body 36.

As depicted in FIG. 19A and FIG. 19B, an embodiment of catheter 30D includes a bulbous head 100. Bulbous head 100 has an outer diameter OD2 greater than outer diameter OD1 of outer surface 69 on catheter body 36. In the embodiment shown in FIG. 19A, the plurality of convex outer surfaces 72 and channels 90 defined therebetween are disposed entirely to one side of bulbous head 100. As depicted in FIG. 19B, convex surfaces 72 being below head 100 such that head 100 includes a substantially smooth and continuous outer surface 102.

As depicted in FIG. 18C and FIG. 19C, outer surface 69 of catheter body 36 including the plurality of convex surfaces 72 has a flower petal-like configuration when viewed in cross-section. Additionally, tubular body 36 in some embodiments may be completely free of openings extending through said body 36 such that the only opening in catheter 30D is entrance opening 38 intersecting longitudinal axis X.

As depicted in FIG. 20, an embodiment of catheter 30E depicts a spherical head 104 formed adjacent the first end of the tubular body member 36 wherein the spherical enlarged head 104 has a diameter greater than that of tubular body 36. The enlarged head 104 on catheter 30E is adapted to guide intermittent urinary catheter 30E through the urethral canal of a patient.

As depicted in FIG. 21, an embodiment of catheter 30F depicts an enlarged head 106 that is generally cylindrical having a uniform diameter along the longitudinal length of head 106. Enlarged cylindrical head 106 may be connected to catheter body 36 via a tapered step down section 108. The cylindrical tip 106 is formed adjacent the first end of catheter 30E and has an outer diameter greater than that of tubular body member 36. Cylindrical tip 106 is adapted to guide the intermittent urinary catheter 30F through the urethral canal of a patient.

As depicted in FIG. 24, an embodiment of catheter 30G includes an enlarged head 109 having a maximum diameter width offset from an imaginary horizontal midline of head 109. Stated otherwise, the bulbous head 109 on catheter 30G has its widest point closely adjacent the first end. The head 109 then tapers inwardly towards the catheter body 36. Head 109 may be configured to have a plurality of convex sections or portion extending there-along, similar to the other embodiment catheters disclosed above. Further, the interior lumen may be defined by any of the described configurations presented above.

As depicted in FIG. 25, an embodiment of catheter 30H depicts an enlarged head having a maximum diameter width offset from an imaginary horizontal midline of head 111. Stated otherwise, the bulbous head 111 on catheter 30H has its widest point closely adjacent the first end. Head 111 is more elongated than head 109. Head 111 tapers at a lower tapering angle relative to body 36 than shown on catheter 30G. Head 111 may be configured to have a plurality of convex sections or portion extending there-along, similar to the other embodiment catheters disclosed above. Further, the interior lumen may be defined by any of the described configurations presented above.

As depicted in FIG. 26, an embodiment of catheter 30I depicts an end of the catheter body 36 tapering inwardly (i.e., towards the longitudinally extending center axis). The inwardly tapering end of catheter 30I defines an entrance opening 112 of the intermittent catheter 30I having a diameter ID8 perpendicularly intersecting the longitudinal axis that is less than the inner diameter ID4 of the lumen. The inwardly curving end of catheter 30I provides strength to the first end. Further, the opening 112 having diameter ID8 less than inner diameter ID4 of lumen may have a venturi-like effect (e.g., increase velocity while decreasing pressure) on the urine draining from the bladder as it enters catheter 30I and moves through opening 112. Opening 112 is aligned along the same longitudinal axis as the lumen of catheter 30I. Opening 112 is distinct from a conventional “eyelet” on a catheter inasmuch as it does not extend radially through the catheter body, rather is defined by an end and extends longitudinally.

In operation, as seen in FIG. 2, the device of the present invention provides a method of draining urine 72 from a human bladder 71. First end 32 of catheter sidewall 36 is first inserted into a urethral canal 70 in a human body until the first end 32 breaches a sphincter wall 73, passes the prostate 74, and is placed in fluid communication with the bladder 71. Bladder 71 contents, namely urine 72, begin to flow toward the first end 32. Urine 72 then flows via gravitational forces over tapered annular recesses 46. Surface 46 tapers inwardly and this permits the fluid to increase velocity or flow rate and decrease its pressure as it approaches entrance opening 38. Urine then passes through entrance opening 38 and longitudinally into lumen 44. As fluid flows through entrance opening 38, it contacts the channels 50. Channels 50 decrease surface side wall friction of the fluid 72 as it exits the bladder 71. The channels 50 on the inner sidewall surface 42 permit fluid 72 to drain faster than a conventional catheter having a smooth inner sidewall side wall 24 as known in the prior art. Fluid exits the lumen 44 through an exit opening (not shown) at the second end 34 of the catheter and to enter a drainage funnel 45. The catheter 30 remains in fluid communication with the bladder until all of the urine or a desired quantity of urine has drained out of the exit opening (not shown) provided at second end 34 of catheter sidewall 36. Once all urine has drained completely, the catheter may be extracted by gripping the second end 34 and extracting the device 30A out of the urethral canal 70.

One advantage of the present invention 30 is that it allows all of the urine to drain out of the bladder. Prior art catheters having eyelets 18 in their sidewalls have been known to not fully drain the bladder as a two eyelet design creates a negative pressure inside the bladder not permitting all urine, fluid or debris contents to drain.

Further, the present invention offers advantages over prior art catheters 10 in that when a patient is sick, the urine 72 may become clogged with mucous or other debris. The entrance opening 38 of the present invention 30 permits mucous and debris to flow readily into lumen 44 and through the catheter without getting clogged or stuck. In prior art catheters 10, clogging problems with the eyelet 18 design are known to occur.

Alternative embodiment 30B of the present invention operates by first aligning truncated tear drop head 56 with urethral canal 70, then inserting head 56 into the urethral canal 70. The head 56 outer diameter OD2 is generally equal to or slightly larger than the upstretched diameter of the urethral canal 70. Catheter 30B is manipulated so the truncated tear drop head 56 advances through the urethral canal 70 until it is in communication with the bladder 71. The head 56 operates as a guide to navigate the natural curvature often found in the urethral canal 70 of males.

Alternative embodiment 30C operates by the first end 32 being first inserted into the urethral canal 70. The convex dimple apices 60B contact the urethral canal 70 during insertion. The convex dimples 60 reduce the surface area of the urethral canal 70 actually contacting the catheter 30C. Thus, dimples 60 reduce irritation often associated with inserting a catheter 10 having a smooth outer surface. Further, retention areas 43 retain a lubricant as catheter 30C moves through the urethral canal 70 towards bladder 71. An exemplary lubricant is commercially sold as Surgilube® manufactured by Savage Laboratories® a division Fougera Pharmaceuticals, Incorporated, A Sandoz Company, of Melville, N.Y. The eyelets of prior art catheters 10 have been known to become clogged or partially clogged with lubricant and thus have decreased flow rates. This problem is obviated in the present catheters 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, or 30I. Once urine 72 begins to flow, the dimples 62 along the inner surface of catheters 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, or 30I cause the fluid to drain faster than it normally would over a smooth inner surface. Similar to a dimpled golf ball, the concave dimples permit urine 72 to pool up in the concave dimple 62 recesses. This reduces the friction factor of the remaining urine 72 draining through the lumen permitting it to increase the drainage flow rate while simultaneously permitting laminar flow through the center of the lumen.

While catheters 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, or 30I of the present invention provide for a single entrance opening defined in the first end of the annular sidewall, it is to be understood that more than one opening are possible. For example, a cross member can extend across the opening offering more strength and rigidity to the sidewall. This cross member would bisect the entrance opening into two or more openings. It is to be appreciated that these two or more openings would still operate in accordance with the aspects of the present invention.

Alternative embodiment 30D by first aligning truncated tear drop head 92 (channeled head) or 100 (smooth head) with urethral canal 70, then inserting head 92 or 100 into the urethral canal 70. The head 92 (channeled head) or 100 (smooth head) outer diameter OD2 is generally equal to or slightly larger than the upstretched diameter of the urethral canal 70. Catheter 30D is manipulated so the truncated tear drop head 92 (channeled head) or 100 (smooth head) advances through the urethral canal 70 until it is in communication with the bladder 71. The head 92 (channeled head) or 100 (smooth head) operates as a guide to navigate the natural curvature often found in the urethral canal 70 of males, but also works equally well for females. Enlarged heads on catheters 30E and 30F operate in a similar guiding manner.

With continued reference to catheter 300, convex outer surfaces 72, namely their respective apices, contact the urethral canal 70 as catheter 30D is advanced towards the bladder. The apices on convex surfaces 72 having a greater diameter than reduce the amount of outer surface area directly contacting urethral canal 70. Further, lubricant may be retained in channel(s) 90 to assist in the frictionally reduced gliding advancement of catheter 30D.

It is contemplated that catheter sidewall 36 will be made from a polyvinylchloride thermoplastic having additional plasticizers to make the PVC material soft and flexible for in vivo use, as conventionally known in the art. However, other materials known in the art such as latex or silicone-based derivatives may be substituted as well. Further, it is preferable that sidewall 36 of urinary catheters 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, or 30I will be made wholly of PVC, or otherwise free of a reinforcing member that is a different material. However, there may be instances in which having a reinforced tube, such as a fully encapsulated reinforcing braid, may be advantageous. Further, it is preferable that sidewall 36 is non-porous so that no bacteria can build up in material recesses, permitting devices 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, or 30I to be cleaned or disinfected and reused.

It will be understood that while the catheters 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, or 30I have been described herein as being useful for draining a single fluid (i.e. urine) from a patient's bladder during a drainage session, they may also be used in other medical procedures. Catheters 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, or 30I may also be used to introduce fluids into a patient's body. Consequently, lumen 44 is able to permit fluid flow out of a patient's body and into a patient's body. It will further be understood that the fluids in question may be liquids or gases.

As depicted in FIG. 22, an alternative internal configuration of any one of the catheters 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, or 30I, is provided. A portion of lumen 44 is defined by longitudinally extending edge 54A connecting adjacent flat panel walls 55A together. Flat panel walls 55A extend towards longitudinal center axis X from their connection with edge 54A. Flat panel walls 55A contact arcuate wall 51. Arcuate wall 51 has a radius of curvature equal to first inner diameter ID1 divided by two. Furthermore, first inner diameter ID1 is measured from arcuate wall 51 through longitudinal axis X to an opposed arcuate wall 51. A second inner diameter ID2 is measured through longitudinal axis X between opposed longitudinal edges 54A. Second inner diameter ID2 is greater than first inner diameter ID1. Channels 50 are defined between flat panel wall 55A and have a v-shaped configuration in cross section. The advantage of this configuration is designed to improve fluid flow through lumen 44 inside a catheter.

As depicted in FIG. 23, the inner surface 42 defining lumen 44 may be scored with a plurality of score lines 110 circumferentially disposed about longitudinal axis X. Score lines 110 extend slightly into the catheter body away from longitudinal axis X. Score lines 110 help to reduce surface tension of fluid moving through lumen 44. In the shown embodiment of FIG. 23, score lines 110 extend longitudinally in a linear manner along the length of the catheter body. However, it is to be clearly understood that the score lines 110 may helically wind about longitudinal axis X creating a rifling effect of the fluid moving through lumen 44 inside the catheter. The score lines 110 are preferably used in association with a catheter having a French size less than about French size 10. However, clearly it is contemplated that larger sizes may be used as well. In one particular example, score lines 110 are provided on a catheter having a French size 4.

In the foregoing description, certain terms have been used for brevity, clearness, and understanding. Namely, the term “non-circular cross section” with reference to the inner or outer surface refers to the annular wall 36 defining the lumen of the catheter not having a continuous circular extending cross section. Specifically, the inner surface is non-circular because it may contain longitudinally extending straight channels, rifled channels, helical channels, textured dimples, staggered recesses, turbulence reducing molding, or other striations that intentionally break the fluid friction or tension which would ordinarily occur against a smooth inner catheter wall. The term “eyeletless” refers to the absence of any eyelet formed in the sidewall of a catheter sidewall as ordinarily understood and used in the prior art; stated otherwise, the term eyeletless refers a catheter annular sidewall that is continuous. The term “dimples” or “dimpled” refers to a plurality of hemispheric recesses formed on a surface. The dimples on the inner surface of the catheter cause a fluid boundary layer entering the lumen from an entrance opening to transition from laminar to turbulent within the hemispheric recess. The turbulent boundary layer within the hemispheric recess is able to remain attached to the inner surface much longer than a purely smooth surface having a laminar boundary and so creates a narrower, low pressure, wake and hence less pressure drag (i.e., friction). The reduction in pressure drag or friction causes the fluid to drain more rapidly.

Again, it is to be clearly understood that the internal geometric configurations of lumen 44 of any catheter embodiment 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, or 30I can be fabricated with any of the outer geometric configurations of catheter embodiment 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, or 30I. So for example, the internally dimpled lumen presented in FIG. 10C may be used in combination with any catheter embodiment 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, and 30I. Additionally, the internal lumen configuration including a flat wall presented in FIG. 6A may be used in combination with any catheter embodiment 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, and 30I.

The term “intermittent” refers to a type of catheter that is not permanent fixture or a repeatably used urine draining device having a balloon seal, such as a Foley-type catheter. Rather, the intermittent catheter 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, and 30I is configured to be inserted into urethral, drain urine a single time, then be removed and discarded.

No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.

Moreover, the description and illustration of the preferred embodiment of the invention are an example and the invention is not limited to the exact details shown or described. 

What is claimed:
 1. An intermittent urinary catheter comprising: a generally flexible tubular body member defining a single lumen extending centrally along a longitudinal axis from a first end to a second end and the tubular body member having a rounded endwall located at the first end connected with an inwardly tapering conical section defining a single entrance opening generally orthogonal to the longitudinal axis, said first end adapted to be advanced through a urethral canal into a bladder of a patient; an outer surface spaced apart from an inner surface of the tubular member, wherein the inner surface defines the single lumen adapted to drain urine from the bladder; and a plurality of distinct longitudinally extending arcuately convex surfaces positioned circumferentially about the longitudinal axis collectively defining the outer surface.
 2. The intermittent urinary catheter of claim 1, wherein the plurality of longitudinally extending arcuately convex surfaces begin adjacent the first end and extend towards the second end.
 3. The intermittent urinary catheter of claim 2, further comprising a bulbous head at the first end having an outer diameter greater than the tubular body member.
 4. The intermittent urinary catheter of claim 3, wherein the bulbous head has a truncated teardrop-shape.
 5. The intermittent urinary catheter of claim 3, wherein the plurality of longitudinally extending arcuately convex surfaces begin at the first end and extend over the bulbous head.
 6. The intermittent urinary catheter of claim 3, wherein the plurality of longitudinally extending convex arcuately surfaces are disposed entirely proximal from the bulbous head.
 7. The intermittent urinary catheter of claim 2, further comprising: a first convex surface; a second convex surface connected to the first convex surface at an edge therebetween defining a longitudinally extending channel.
 8. The intermittent urinary catheter of claim 7, further comprising: the plurality of longitudinally extending arcuately convex surfaces in a range from four convex surfaces to twelve convex surfaces and longitudinally extending channels defined between connected convex surfaces.
 9. The intermittent urinary catheter of claim 8, further comprising: a plurality of inner longitudinally extending arcuately concave surfaces circumferentially positioned about the longitudinal axis collectively defining the inner surface of the tubular body.
 10. The intermittent urinary catheter of claim 9, wherein the number of the plurality of inner arcuately concave surfaces equals the number of outer convex surfaces.
 11. The intermittent urinary catheter of claim 9, wherein the number of the plurality of inner arcuately concave surfaces is different than the number of outer convex surfaces.
 12. The intermittent urinary catheter of claim 1, wherein the plurality of longitudinally extending arcuately convex surfaces begin at the first end.
 13. The intermittent urinary catheter of claim 1, wherein the outer surface of the tubular body member when viewed in cross section creates a flower petal-like configuration.
 14. The intermittent urinary catheter of claim 1, wherein the tubular body member is free of any radially extending openings and is substantially continuous from first to second ends.
 15. The intermittent urinary catheter of claim 1, further comprising: a radius of curvature for one of the plurality of distinct longitudinally extending convex surfaces, and the radius of curvature is determined by: $R_{curv} = \frac{OD}{N}$ wherein R_(curv) equals the radius of curvature, OD equals an outer diameter measured across the outer surface, and N equals the number of convex surfaces; and the radius of curvature in a range from about 0.1 mm to about 1.3 mm.
 16. The intermittent urinary catheter of claim 15, wherein the radius of curvature is the same for each one of the plurality of distinct longitudinally extending arcuately convex surfaces.
 17. The intermittent urinary catheter of claim 1, wherein the inner surface of the tubular body member is non-circular in cross-section.
 18. The intermittent urinary catheter of claim 1, further comprising a plurality of arcuately concave channels provided in the inner surface of the sidewall, where each channel extends longitudinally from adjacent said entrance opening and towards said second end.
 19. An intermittent urinary catheter comprising: a generally flexible tubular body member defining a lumen extending centrally along a longitudinal axis from a first end to a second end, said first end adapted to be inserted into a urethral canal of a patient, an outer surface spaced apart from an inner surface of the tubular member, wherein the inner surface defines the lumen adapted to drain the fluid from the patient's bladder; a longitudinally aligned entrance opening formed at the first end of the of the tubular body member in fluid communication with the lumen; and a score line formed in the inner surface extending slightly into the tubular body member in a radial manner relative to the longitudinal axis and configured to reduce surface tension of fluid through the lumen.
 20. A catheter comprising: a tubular body extending centrally along a longitudinal axis from a first end to a second end; the tubular body including an outer surface spaced apart from an inner surface, and wherein the inner surface defines a lumen; an entrance opening formed at the first end of the tubular body in fluid communication with the lumen, and a plane associated with the entrance opening intersecting the longitudinal axis; an enlarged head at the first end including an outer diameter greater than that of the tubular body; a plurality of distinct longitudinally extending convex surfaces positioned circumferentially about the longitudinal axis collectively defining the outer surface of the tubular body; and a plurality of distinct longitudinally extending concave surfaces positioned circumferentially about the longitudinal axis collectively defining the inner surface of the tubular body. 